chan_sip: Fix missed locking of opposing pvt for directmedia acl from r366547

It also required deadlock avoidance since two sip_pvts structs needed to be
locked simultaneously. Trunk handles it differently, so this is a 1.8 and 10
patch only.

(issue AST-876)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@366791 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -29083,11 +29083,19 @@ static struct ast_udptl *sip_get_udptl_peer(struct ast_channel *chan)
 	}
 
 	sip_pvt_lock(p);
+	while (sip_pvt_trylock(opp)) {
+		sip_pvt_unlock(p);
+		usleep(1);
+		sip_pvt_lock(p);
+	}
+
 	if (p->udptl && ast_test_flag(&p->flags[0], SIP_DIRECT_MEDIA)) {
 		if (apply_directmedia_ha(p, opp, "UDPTL T.38 data")) {
 			udptl = p->udptl;
 		}
 	}
+
+	sip_pvt_unlock(opp);
 	sip_pvt_unlock(p);
 	return udptl;
 }
@@ -29153,7 +29161,14 @@ static enum ast_rtp_glue_result sip_get_rtp_peer(struct ast_channel *chan, struc
 	}
 
 	sip_pvt_lock(p);
+	while (sip_pvt_trylock(opp)) {
+		sip_pvt_unlock(p);
+		usleep(1);
+		sip_pvt_lock(p);
+	}
+
 	if (!(p->rtp)) {
+		sip_pvt_unlock(opp);
 		sip_pvt_unlock(p);
 		return AST_RTP_GLUE_RESULT_FORBID;
 	}
@@ -29172,6 +29187,8 @@ static enum ast_rtp_glue_result sip_get_rtp_peer(struct ast_channel *chan, struc
 		res = AST_RTP_GLUE_RESULT_FORBID;
 	}
 
+	sip_pvt_unlock(opp);
+
 	if (p->srtp) {
 		res = AST_RTP_GLUE_RESULT_FORBID;
 	}
@@ -29199,7 +29216,14 @@ static enum ast_rtp_glue_result sip_get_vrtp_peer(struct ast_channel *chan, stru
 	}
 
 	sip_pvt_lock(p);
+	while (sip_pvt_trylock(opp)) {
+		sip_pvt_unlock(p);
+		usleep(1);
+		sip_pvt_lock(p);
+	}
+
 	if (!(p->vrtp)) {
+		sip_pvt_unlock(opp);
 		sip_pvt_unlock(p);
 		return AST_RTP_GLUE_RESULT_FORBID;
 	}
@@ -29214,6 +29238,7 @@ static enum ast_rtp_glue_result sip_get_vrtp_peer(struct ast_channel *chan, stru
 		}
 	}
 
+	sip_pvt_unlock(opp);
 	sip_pvt_unlock(p);
 
 	return res;
@@ -29237,7 +29262,14 @@ static enum ast_rtp_glue_result sip_get_trtp_peer(struct ast_channel *chan, stru
 	}
 
 	sip_pvt_lock(p);
+	while (sip_pvt_trylock(opp)) {
+		sip_pvt_unlock(p);
+		usleep(1);
+		sip_pvt_lock(p);
+	}
+
 	if (!(p->trtp)) {
+		sip_pvt_unlock(opp);
 		sip_pvt_unlock(p);
 		return AST_RTP_GLUE_RESULT_FORBID;
 	}
@@ -29252,6 +29284,7 @@ static enum ast_rtp_glue_result sip_get_trtp_peer(struct ast_channel *chan, stru
 		}
 	}
 
+	sip_pvt_unlock(opp);
 	sip_pvt_unlock(p);
 
 	return res;